Sunil Yapa’s debut novel plunks you down smack dab in the middle of Seattle’s rambunctious 1999 World Trade Organization protests and gives you precious little respite from the boisterous demonstrators, jittery and aggressive police and escalating chaos. Marred only slightly by uneven character development, this furiously paced and contrapuntal literary tour-de-force makes use of multiple vantage points and benefits from a remarkably empathic sensibility on the part of its author. No wonder publisher Little, Brown and Co., selected Your Heart Is a Muscle the Size of a Fist to launch its Lee Boudreaux imprint.

Sensitive and acutely aware of his biracial (black-white) identity, Victor is the most arresting of the seven characters whose minds the roving third-person narrator inhabits. “It was 1999 in America, [Victor] had traveled the world for three years, looking for what he didn’t know, and now here he found himself: absolutely allergic to belief, nineteen years old and totally alone.”

Victor views the protests as a sterling opportunity to sell the marijuana stashed in his backpack but is waylaid by the intense and persuasive King and her kind-hearted bear of a boyfriend, John Henry, dedicated anti-globalization activists. Now Victor wants to contribute to the cause, despite his lack of training in non-violent resistance.

Meanwhile, Chief of Police Bishop, a keenly introspective man who hasn’t seen his estranged stepson Victor in three years and doesn’t realize he’s on the scene, receives orders to disperse the protesters and escort the besieged WTO delegates from their hotel to the convention center.

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As Victor and a handful of others go into lockdown, sitting “cross-legged on the pavement with both arms locked into PVC pipe, each arm locked from the inside with a chain to a person on either side,” Bishop leads his overstretched and increasingly restive force into the fray. Soon he’s witnessing “the backs of his troops’ hooded forms chopping through the crowd.”

With your senses assailed by such frenetic and relentless action, you’ll want to chide Yapa that he didn’t have to aim for a wallop a minute. Fortunately, the periodic contemplative chapters about Sri Lanka’s Deputy Minister of Finance and Planning, Charles Wickramsinghe, give your fist-sized heart a break. They also infuse the story with intellectual substance and complexity; Yapa (born to an American mother and a Sri Lankan father) thrusts Wickramsinghe, who aims to clinch Sri Lanka’s accession to the WTO, into encounters with protesters who have undertaken their “direct action” on behalf of people such as his own.

For dramatic ballast, Yapa endows his seven main characters with backstories replete with loss and anguish. Victor has never overcome the death of his mother; until these protests, he’d failed to recapture that sense of life purpose with which their shared charitable work imbued him.

Meanwhile, Bishop has had to contend with widowhood and the disappearance of the disaffected Victor. One of Bishop’s officers, Timothy Park, an intriguing character Yapa fails to flesh out, suffered a facial injury in the Oklahoma City bombing of 1995 and harbors a hatred of anything anti-government; his partner on the force is Julia, who left Los Angeles because of the 1992 riots. King, who helps initiate Victor into non-violent protest, remains haunted by a shocking act of violence she committed years ago.

With Yapa burrowing into the hearts of these characters, each distinct yet sufferers all, his already weighty story attains a level of profundity. Your Heart Is a Muscle the Size of a Fist ultimately explores the myriad ways we react to searing emotional pain. There’s always the hopeful prospect that, with proper nurturing, it will arouse our too-often dormant empathic inclinations. But lurking underneath is the disturbing alternative that, if we allow it to, such trauma will numb and harden us and even lead to cruelty.